Display system for moving vehicles



M. ARENDT 2,299,731

Filed April 16, 1940' 2 Sheets-Sheet l DISPLAY SYSTEM FOR MOVING VEHICLES Y @5 @S l HPS l Q m7 w m .r 1J I l R N @1 m r r i 1 T ,wN 4 ,A CSQ Nlu k\ GY IWI kw m g k o, Il Er M u Q u m u i Las@ -l s w .H NN g w g N Erl w -if w Y@ N @www www0 HUMO! N ,Q Q Q w .w r ,F V .k Hrw. www1 IM LYNN lmlY l P l/ l NI .l l Il m@ .l I.- l I. W4. uw. .H 4 im w .w ww www Oct. 27, 1942.

, Oct. 27, 19,42. M. ARENDT 2,299,731

DISPLAY SYSTEM FOR MOVING VEHICLES Filed April 16, 1940 2 Sheets-Sheet 2 if +I 6 DIRECT CURRENT Q QU if DIREC CURRENT INVENTOR. M05 70A/ ,mf/var /Z Lw ATTORNEY Patented Oct. 27, 1942 UNITED STATES PATENT OFFICE 2,299,731 DISPLAY SYSTEM FOR MOVING VEHICLES Morton Arendt, New York, N. Y. Application April 16, 1940, Serial No. 329,887

9 Claims.

This invention relates to display systems and more particularly to novel systems for observing pictures installed along the path of a moving vehicle by passengers on the vehicle, of the general type disclosed in U. S. Letters Patent No. 2,026,753 granted on Jan. 7, 1936, to Leon W. Rosenthal and Jerome Meyer, entitled Display device.

In accordance with the present invention, successive display scenes are spacedly mounted alongside the path of a moving vehicle, such as a subway train, elevator, escalator or the like. Sources of illumination are arranged adjacent each picture and are interconnected to an energizing circuit actuated in accordance with the movement of the vehicle through the installation. Illumination of the pictures is by brilliant flashes of extremely short duration, obviating the possibility of blurring in observation of the pictures. The speed of the vehicle may become relatively high with a smooth continuous display effect prevailing despite variations in the speed.

Novel circuit arrangements are incorporated in the present invention, rendering the system commercially practical and expedient to install, maintain and service. Breakdown o1' an i1lumination source in no way afl'ects the operation or observation of the system. The preferred illumination sources are in the form of gaseous tubes having a continuous power potential. The tubes are illuminated by ilashes derived from high voltage signal impulses of very short duration. Actuating means for the groups of lamps associated with the pictures are provided at a plurality of points along the installation to insure continuous operation of all the pictures in the installation while any portion of the vehicle is passing therethrough.

Inalinodiiication of the invention, the installationl is divided into a number of adjacent sections, of the order oi.' one hundred feet in length, to prevent illumination of the installation far in front of the vehicle. The successive sections of the installation are energized ahead of the ve hicle, and the sections remain actuated untilthe rear of'the vehicle passes through. In another form of the invention, the successive pictures of an installation at an approach to a station consist of identical pictures or printing. Upon deceleration of the vehicle a stationary message is conveyed to the observers, such as the name of the station approached and advertising matter.

In a further form of the invention, alternate pic-- tures and their associated illumination sources are omitted to reduce cost of the installation.

' sentation, image or the like.

It is accordingly among the objects of the present invention to provide novel arrangements whereby outside stationary pictures may be observed by passengers on a vehicle traveling at high speed, imparting an animated or still display; to provide individual instantaneous flashing light sources for the successive pictures; to provide a plurality of energizing means for the illumination sources operable by different sectionsfof the moving vehicle'; to provide novel circuit arrangements for instantaneously flashing the individual illumination sources; and to provide other novel arrangements for such systems as the omission of alternate pictures, and otherwise rendering the installations practical and serviceable under continuous operating conditions.

The foregoing and other objects, advantages, and capabilities of the invention will become more apparent in the following description of embodiments thereof illustrated in the drawings, in which:

Fig. l is a diagrammatic illustration of one embodiment of the invention in connection with a subway installation; Fig. 2 is a. schematic electrical diagram of a preferred illumination source arrangement and associated circuits; Fig. 3 is a schematic electrical diagram of the photo-electric cell and impulse generating circuit; Fig. 4 is a schematic arrangement of a modified form of the invention; Fig. 5 is a diagrammatic illustration of a further modification of the invention, omitting alternate pictures of the series; Fig. 6 is a perspective illustration of a picture and associated illumination source as installed; Fig. 7 is a diagrammatic illustration of a modified manner of connecting the individual light sources.

A complete installation of one form of my system for a subway is diagrammatically illustrated in Fig. l. Two series of pictures l0 are spacedly arranged on opposite sides of tracks Il so as to be readily viewed through the spaced windows I 2 of cars I5 of a passing subway train. By the expressions picture or scene I refer to any type of display scene, character, view, printing, repre- The spacing between centers of pictures Iltis made to correspond to the average spacing between centers of windows l2 of the cars. Each picture l U is individually and locally illuminated by sources of illumination 20 in a manner to be described in detail. Illumination sources, gaseous lamps 20, are connected in parallel through cables 2|, 22, 2s to a single energizing unit 25. Illumination by lamps 20 is in theform of successive brilliant flashes in synchronism with the travel of cars I5, controlled by photo-electric cells 26 and 21 respectively mounted at the beginning and end of the picture series.

Photo-electric cells 26 and 27 are connected to the input of energizing unit 25 by leads 28 and 29 which leads are preferably electrostatically shielded. A series of shadow plates 30 extend vertically from the'catwalk or otherwise centrally along the top of each car I5. They are arranged to intercept light beams 3|, 32 respectively directed on photo-electric cells 26, 21. Lamps 33 and 34 are mounted opposite the respective photo-electric cells 26, 21, with their beams 3l, 32 directed on the cells. Photo-cells 26, 21 and lamps 33, 34 are located at a level above tracks II so that beams 3|, 32 are successively intercepted by the spaced shadow plates 30 on passing cars I5. Other arrangements of the photo-electric cells and shadow plates may be used. Precautions are preferably taken to prevent extraneous light from impinging upon photo-electric cells 26, 21 to maintain the interception of .light beams 3|, 32 by shadow plates 30 ata maximum effectiveness. This is most readily accomplished by maintaining the photo-electric cells above car window levels and by proper tubular shields.

The spacing between centers of shadow plates 30 along the cars I5 is made identical with the spacing between centers of stationary pictures. I0. The series of shadow plates 30 along all the cars I5 is preferably continuous, as illustrated in Fig. 1. The spacing for pictures I and shadow plates 30, while corresponding to the spacing between centers of windows I2 of the subway cars, is chosen so that the shadow plates 30 are symmetrical and similar with respect to each car. Thus, the series of shadow plates 30 will function continuously and regularly regardless of the manner in which the cars I are coupled together to constitute the train. Smooth and regular operation of the animated projection display system will accordingly be assured for any combination of cars and trains entering and leaving the display section as will be more evident hereinafter.

When the rst car of the train enters at the left side of the picture installation, light beam 3| will be first successively intercepted by the shadow plates 30 on the first car. The interruption of beam 3I continues until the last car passes the beam, the latter condition being indicated in Fig. 1. The provision of light beam 32 and associated photo-electric cell 21 at the right end of the installation insures continuous operation of the display system until 'the last car of the train completely left the display installation.

Photo-electric cells 26 and 21 are connected in parallel for joint and individual actuation of the control device 25. Light beam 32 is interrupted by the shadow plates remaining in the section, causing a corresponding interruption of light reaching the photo-cell 21. These interruptions of beam 32 initiate the source 20 energizing impulses by unit 25.- An important feature of the arrangement herein resides in that when the light beams to both photo-cells 26 and 21 are interrupted, no interference occurs in the control ac- 'tion of the photo-cells on unit 25. Thus, irregularities in the space phase of the shadow plates opposite photo-cells 26 and 21 at any given time as mayoccur in practice, in no way interfere with corespondingly illuminating all the associated pictures I0 in the subway section. The energization of sources o r lamps occurs abruptly. the illumination instantly reaching its maximum value. The illumination is in the form of brilliant .flashes a'bove each picture I0, timed to occur when the pictures areV substantially opposite windows I2 of cars I5.y The abrupt flashes occur successively, in synchronism with the speed of travel of the train. The shadow plates, spaced in accordance with the average spacing between windows I2, initiate the abrupt and brilliant light flashes opposite each picture I0 as each successive picture reaches a predetermined iield of view of any observer in the VIrain.

No blurring of the picture occurs regardless of the speed .of the observer. Successive progression of the illuminated pictures imparts a smooth and continuous optical effect to all observers. By arranging eachsuccessive picture as a successive frame of a motion picture display, corresponding to the successiveframes of a standard motion picture projection system, a continuous animated or motion picture effect is produced. By suitably spacing pictures IU, lany one observer will see only one picture at a time. Also, in view of similar action being effected on all the pictures in the subway section, all observers in the cars will see the animated display in different phases of projection, depending on his relative location on the moving train. Irregular spacing between windows I2 of particular cars or trains in no way disturbes the animated view for any observer since his line. of vision to the display pictures remains constant due to the correspondence of the spacings between the shadow plates 30 and that of the pictures I0.

In a particular embodiment of the invention, the average spacing between the centers of windows I2 of subway cars I5 is about 26 inches. .For this case pictures I0 may well vbe anywhere between 12 and 16 inches in width, with corresponding spacings between adjacent picture edges of 14 to 10 inches respectively. With a 26 inch spacing between lcenters of successive pictures ID, about twenty'pictures or frames pass an observer in a car traveling at a speed of 30 miles per hour. For a continuous motion picture effect, a minimum passage of 15 frames lper second is desirable, occurring at the minimum train speed through the section. For example, where the system of the invention is installed in a track section designed for an average speed of train passage of 30 miles per hour, a smooth and normal animated display will be apparent to observers on the train if it should travel in the range from about 20 to 50 miles per hour throughthe section.

The present invention overcomes practical diiculties encountered in prior art systems. By utilizing the brilliant rapidly ilashing light sources 20 for each spaced picture I0, and by controlling the energization of the sources 2'0, substantially instantaneously accurate synchronization of the light flashes is effected with respect to the interruptions of the light beams 3I, 32 by shadow plates 30. Furthermore, by connecting the individual `light sources 20 in parallel, impractically excessive high operating voltages are avoided.

Fig. 2 is a schematic electric diagram of a preferred circuit arrangement for controlling the ilashing of the light sources 20. Each light source 20 is in the formof a gaseous tubular lamp. Tubes 20 are connected in parallel to three-wire cable 2| for simultaneous operation. A fourth wire may be used where local departmental regulations require it. A direct currentsource 35 is connected between leads 36, 31, 36 of three-wire cable 2|. The negative terminal of source 35 is grounded as is lead 38, the positive terminal of source 35 being directly connected to lead 36.

The ends of lamps 20 are all connected in parallel through respective resistors 40. Resistors 40, connected to `positive lead 36, are ballast resistors in series with the respective lamps to prevent any defective lamp in the series from short-circuiting the parallel energizing circuit. In a practical embodiment, with lamps 20 fifteen inches long and about one-half inch in diameter, the voltage of generator 35 was one thousand volts and ballast resistors 40 each 2000 ohms. Capacity connections 4l on lamps 20 are made to lead 31 of cable 2|, in turn connected to the ungrounded side of the secondary winding 42 of transformer 44. The side of secondary winding 42 preferably grounded is its positive side. Connections 4| serves as a trigger impulse connection for instantaneously igniting gaseous lamps 20. With a direct current lighting or power source of one thousand volts at 35, an impulse voltage of the order of fifteen thousand volts across secondary winding 42 and leads 31, 36, instantaneously ignites all the lamps 20. The lighting action is as a bright flash, locally on each picture I0. A condenser 46 is shunted across each gaseous tube 20 to store up energy from the power source 35 connected thereacross,

the described arrangement.

The generation of the ignition impulse across secondary winding 42 is initiated through photoelectric cells 26 or 21. The photo-electric cells are connected, through leads 26 and 29 respectively, to the input of photo-electric cell circuit unit 45. When the light beam impinging upon either photo-electric cell 26 or 21 is interrupted by a shadow plate 30, an electrical impulse is generated in photo-cell unit 45, in a manner to be described in conjunction with Fig. 3, causing an abrupt voltage impulse across tion with the high step-up ratio of transformer 44 produces the required trigger voltage across secondary winding 42. The trigger voltage conditiony is an instantaneous phenomenon in the circuit arrangement, causing an instantaneous ignition of gaseous tubes 20 of very short duration. The duration of the light flashing by tubes 20 is substantially less than one-thousandth of a pictures I brought into view.

Fig. 3 is a schematic electrical diagram of a preferred arrangement for the impulse generating circuit 25 actuated by photo-electric cells 26, 21. Photo-electric cells 26, 21 are connected in parallel through leads.26, 279. The anodes of photo-cells 26, 21 are connected to the grid electrode 6I of triode amplifier 50. The photo-cell anodes and the grid electrode are connected to ground through a very high resistance 52, such I nected between cathode 54 variable tap 62 10.

Ainiziai 53 of the order of volts was used in the given embodiment. Resistance 55 is conof triode 5U and a lead 56 connected to the cathodes of photo-cells 26, 21.

The anode of triode 50 is connected to the positive terminal 51 of the B supply, through resistance 58. A potentiometer 60 is connected across cathode resistance 55 through resistance 6|. The of potentiometer 60 is directly connected to the control grid 63 of highly efficient beam power tube is preferred, with screen grid electrode 66 thereof connected directly to anode 61. Cathode 68 of tube 65 is connected directly to ground. The output of power amplifier tube 65 is connected to primary Winding 43 of step-up transformer 44.

The operating voltage supplies for the eleccycle supply connected to primary winding 69 of transformer 10. The biasing supply for photoelectric cells 25, 21 is generated by a low voltage secondary Winding 1I, one terminal of which is connected to the anode of a diode rectifier 12 the cathode of which is grounded, and the other terminal to the input of a resistance-capacity filter 13. The output terminal 53 of filter 13 is at a negative potential with respect to ground as albiasing the photoof transformer 10, the outer terminals of which are connected to the anodes of full-wave embodiment, the potential, across primary winding 43 of transformer 44 was of the order of 250 volts.

The operation of in producing the impulse actuation voltages for of tube 50. In other words, triode 56 is biased to cut-off during the quiescent period of the circuit. When the light beam impinging on either photo-electric cell 26 or 21 is interrupted by a shadow plate 30 Current correspondingly instantly flows between cathode 54 and the anode of triode 50, causing a current flow through cathode resistor 55.

Such current fiow or change of current flow through resistor 55 produces a relative positive potential thereacross, which positive potential is in turn communicated directly to control grid 63 of output tube 65. The sensitivity or magnitude of the control grid voltage applied to tube 65 is adjustable through tap 62 of potentiometer 'Ihe positive impulse or signal applied to control grid 63 of tube 65 causes a corresponding instantaneous current surge through the primary winding 43 of transformer 44. The signal impulse on primary winding 43 is reflected into a trigger voltage of correspondingly greater magnitude due to the high step-up ratio of transformer 44. 4A step-up ratio of 50:1 was used in the embodiment, giving the desired 15,000 volt trigger impulse for lamps 20. Transformer 44 is of the constant potential type. It is to be understood that other equivalent circuit arrangements may be used for this action.

The trigger action by the circuits of the invention is instantaneous and requires no interruption of air gaps or other mechanical arrangements. No time lag is apparent, and no arcing is incurred. 'I'he transient or impulse action of the circuit results in a flashing action by the gaseous tubes 20, giving the desirable instantaneous illumination on the pictures. In the event that the light beams for both photo-electric cells 26 and 21 are cut-off at the same time, no interfering eect occurs since the circuit is designed to give the full voltage impulse output in response to action by a single photo-cell. The trigger voltage is thus generated by the rst photo-electric cell (26 or 21) which has its light beam interrupted by a shadow plate in each cycle. A relative space phase displacement' between the shadow plates does not upset the circuit action, since the plate which rst interrupted the beam to its associated photo-electric cell initiates the trigger action on lamps 20.

An important aspect of my present invention is that the impulse or trigger voltage action by the circuit is impulsive and rapid, being independent of the length of the shadow plates or their speed of travel. Only one impulse occurs for any single light ,beam interruption, the next successive impulse being generated only upon reimpringement of the light beam on the photoelectric cell and its subsequent interruption. All successive trigger impulses are of the same short duration, producing the corresponding light ilashes for the pictures I8. The length of the shadow plates as compared to the spacing between pictures may be made relatively small, for example, less than 20 per cent, the limit being the width o i the light beams. However, the plates 39 may be advantageously made of the order of 50 per cent of the picture spacing, to allow for space phase displacement of the shadow plates along the train as may be encountered in practice, with no change in the impulse trigger action.-

In the system described in connection with Fig. 1, the complete installation becomes illuminated ahead of the motorman on the rst car of the train entering the section. In the system of Fig. 4, a modification of the invention, only successive parts of the section are illuminated as the train progresses through it. -There is thus no interference with train signals nor is undue lighting presented ahead of the motorman. By dividing the picture installation and associated light sources into successive banks of about single car lengths, or of the order of one hundred feet, no practical interference will result with the eld of view ahead of the motorman. Also the construction and design of the separate impulse ampliers for each bank is simplified.

The successive sections or banks of pictures and associated lamps are indicated schematically at 80, 80 in Fig. 4. Banks 80, S0' contain the successively mounted picture I and associated lamps on opposite sides of the track Il, corresponding to those indicated in Fig. 1. Each bank is preferably of the order of 100 feet in length or the length of a car.

Picture banks on opposite sides of the track Il are electrically connected in parallel by three-Wire cable 8|. A common source of direct current 82 is used for all banks B0, connected thereto through leads A separate photo-electric cell 85 and associated impulse generator 86 is shown in Fig. 4 for each set of banks 80, 89'. This is a schematic representation thereof as will bevexplained hereinafter. Light sources 81 form beams 88 irnpinging on the respective photo-electric cells arranged between adjacent banks. Output leads 89 of impulse generator B6 are connected to the respective banks 80, 80', corresponding to leads 31, 38 of the system shown in Fig. 2. As the shadow plates 30 on cars I5 intercept their respective light beams 88, the associated lamp banks 80, 80' are successively illuminated as will now be evident to those skilled in the art. Those banks only are illuminated opposite which there is a portion of a car l5. The direction of travel of the train of Fig. 4 is from right to left so that the photo-cells 85 are actuated by the shadow plates 30 while any car portion is opposite the associated picture bank.

In the illustrated arrangement of Fig. 4, the head car of the train will have an irregular display action. Only one photo-electric cell is there shown to contro1 each bank 80, 80 for the purpose of simplifying the representation. However, it is to be understood that a double photoelectric cell arrangement similar to that described in connection with Figs. 1, 2 and 3 may be used for each unit 86. Thus, by connecting a separate photo-cell in parallel with each cell 85 and arranging the extra cell at the end of bank 80 opposite that of its associated cell 85, and with a separate light beam for it, a normal display action will result for the lead car as well.

The expense of an installation may be substantially reduced by halving the number of required pictures and associated light sources through doubling their spacing but maintaining the original shadow plate spacing. Fig. 5. illustrates such arrangement wherein pictures 90A correspond to pictures I0 of Fig. 1. Ihe spacing between pictures 90 corresponds to twice the distance between centers of windows 9| of the subway car 92. A source of illumination 93, corresponding to lamps 20 of the previous figures, is`

arranged to illuminate each picture 90 by the flashing action described. A common cable 94, interconnecting lamps 93 for energization thereof, is connected to the energizing sources for the lamps as previously described. Shadow plates S5 are arranged on top of car 92 as in the previous modifications, with spacings between centers of shadow plates 95 corresponding to the spacing between centers of adjacent windows 9|.

The frequency of illumination of the respective pictures 90 will be identical with that of the previous forms, since this is controlled by the spaced shadow plates 95 and the speed of Athe train. The spacing between pictures 90 is such that observers will successively see the.illuminated pictures, with blank spaces occurring successively between picture positions. When an observer is moved opposite successive pictures, they are flashed in his view in proper space phase to overlap the picture he had previously seen. The spacing between shadow plates 95 and pictures 90, while corresponding to the spacing between the centers of windows 9|, is designed to present a minimum of 15 pictures per section to an observer on the train, at the average speed of the |0|, foi` trigger igniting the lamp by the impulse signal voltage applied between |02 and |03, corresponding to leads 31, 38 of Fig. 2. Resistance |04 and capacitance |5 are similar to resistance 40 and condenser 46 of |0| `arrangegaseous tube |00 than that required with the single tap 4| of Fig. 2.

train decelerates upon ap- The display picelevators, escalators and the like. are spacedly arranged ment of the vehicle.

or car is moved with stallation, the photoelectric cell The pictures along the path of move- Where only and associated circuits, as Well as the flashing lamps for illuminating the pictures, are preferably carried by the vehicle. In my copending application, Serial No. 335,277, filed photo-cell as shown in the copending application herein referred to.

Although I have disclosed preferred embodiments for carrying out my present invention, it

made therein falling Within the broader spirit and scope thereof, as expressed in the appended claims.

tions that are independent of the vehicle speed, A

said electronic means comprising two photo-electric cells spaced of the order of the length of said vehicle, an amplifier connected with said photo-electric cells, and a transformer coupled between said lamp means and said amplier, whereby changes iii-illumination on either of said spaced photo-electric cells produces corresponding igniting voltages across said lamp means.

6. The combination with a vehicle having spaced windows, of a plurality of stationary display scenes linearly spaced apart substantially twice the average spacing between said windows, illumination means for said display scenes, shadow plates extending along said vehicle with a spacing substantially equal to said window spacing, and means responsive to the passage of said shadow plates for intermittently igniting said illuminating means at the frequency y of the shadow plate passage, whereby said displayI scenes may be `operatively viewed by observers through any of 'said windows.

7. The combination with av vehicle having substantially regularly spaced windows, of a plurality oi stationary display'scenes linearly arranged along the path of said-vehicle with a regular spacing that is substantiallyA a.v average spacing of said windows, gaseous lamps arranged to intermittently illuminate said display scenes, shadow plates extending along said vehicle regularly spaced apart by distances substanby distances tially equal to said window spacing. and means responsive to the passage of said shadow plates for successively igniting said gaseous lamps at the frequency of passage of said shadow plates, whereby said display scenes are operatively observed by passengers on said vehicle through any of said windows.

8. In a display system, a plurality of stationary linearly spaced scenes having identical display characteristics arranged in the path where a vehicle generally accelerates or decelerates its speed of travel, discharge lamp means for said scenes, and means including circuit connections for successively ashing said discharge lamp means in ashes of very short durations that are independent oi the vehicle speed and at intervals synchronized with the speed of passage of said vehicle, whereby said scenes appear as a stationary display to observers on the accelerating or decelerating vehicle.

9. In a display system, a plurality of stationary linearly spaced display scenes, a plurality or discharge lamps for illuminating said display scenes, means including circuit arrangements connecting said lamps into successive banks of predetermined lengths that are shorter than the length of a train o! cars passing said scenes, and electronic means individual to each of said banks and responsive to the passage of the cars for intermittently flashing the lamps of the respective banks while a car is passing a respective bank, said electronic means being individually coupled to the respective lamp banks for enacting the flashing thereof in short durations that are independent of the train speed.

MORTON ARENDT. 

